The present invention relates generally to ophthalmic lenses, and more particularly, to intraocular lenses (IOLs) that provide enhanced vision via controlled variation of the phase shift across a transition region provided on at least one of the lens surfaces.
Intraocular lenses (IOLs) are routinely implanted in patients' eyes during cataract surgery to replace the natural crystalline lens. The optical power of the natural crystalline lens can vary under the influence of the ciliary muscles to provide accommodation for viewing objects at different distances from the eye. Many IOLs, however, provide a monofocal power with no provision for accommodation. Mutlifocal IOLs are also known that provide a distance optical power as well as a near optical power (e.g., by employing diffractive structures), thereby providing a degree of pseudoaccommodation.
There is, however, still a need for improved IOLs that can provide pseudo-accommodative optical power while providing sharp optical images over a wide range of pupil sizes. In designing IOLs and lenses generally, optical performance can be determined by measurements using a so-called “model eye” or by calculations, such as predictive ray tracing. Typically, such measurements and calculations are performed based on light from a narrow selected region of the visible spectrum to minimize chromatic aberrations. This narrow region is known as the “design wavelength.”